Abstract: A method of treating a metal carbonate salt includes hydrolyzing a metal halide salt to form a hydrohalic acid and a hydroxide salt of the metal in the metal halide salt. The metal includes an alkaline earth metal or an alkali metal. The method includes reacting the hydrohalic acid with the metal carbonate salt, wherein the metal carbonate salt is a carbonate salt of the alkaline earth metal or alkali metal, to form CO2 and the metal halide salt. At least some of the metal halide salt formed from the reacting of the hydrohalic acid with the metal carbonate salt is recycled as at least some of the metal halide salt in the hydrolyzing of the metal halide salt to form the hydrohalic acid and the hydroxide salt.

Abstract: Provided is a filtration system and process that enhances mineral removal from sludge through a novel recirculation and mixing apparatus. In one example, the system may include a filter configured to remove minerals from sludge, a pump configured to move the sludge towards the filter, a pre-filtering system configured to add an agent into the sludge prior to the sludge making contact with the filter, a drainage collection system including one ore more reservoirs configured to collect water drained during and/or after the filtering and feedback the drained water to the pump, and valving configured configured to mix the drained water with the sludge to generate a mixture which is moved by the pump towards the filter.

Abstract: A method of removing solids from a drilling fluid that includes applying a first electric current to a first screen of a screen assembly within a vibratory screening machine; passing the drilling fluid through the screen assembly while the first electric current is applied to allow electroseparation of solids within the drilling fluid; and removing electroseparated solids from the drilling fluid.

Abstract: Disclosed are methods, materials and devices for approximation of blood volume in a fluid, such as in a biological fluid collected during a surgical procedure. The method and devices include the use of a RBC flocculant, such as polyDADMAC, and an approximate blood hematocrit for the type of animal, as well as a calculated RBC packing ratio corresponding to the collection device being used. Also provided is a Blood Indicator Panel (BIP), comprising a series of markings calculated from an observed red blood settlement volume, the average animal type hematocrit, and a calculated RBC packing ratio “?” value for the collection device. Pediatric (about 200 ml or 250 ml size container), adult human (about 1,000 ml-1,500 ml) and veterinary (about 500 ml-2,500 ml) collection containers are also disclosed, that include a RBC flocculant, for use in approximating blood volume in a fluid. Methods of detecting blood in a sample, such as a fluid sample, and kits for performing the methods, are also provided.

Abstract: A method for production refactoring of a company comprises quantifying risks stemming from regulations, in particular from an introduction of new regulation. It further comprises identifying actions to take in order to reduce an exposure to risk, quantifying costs of said actions and determining a revenue at risk depending on a revenue and a probability of failure representing said risks. Furthermore, it comprises determining a sequence of actions for solving an improvement problem depending on said revenue at risk and said costs of said actions and profits reducing said revenue at risks and said costs of said actions and increasing said profits.

Abstract: A calcium fluoride precipitation inhibitor is added to waste water containing sulfuric acid, fluorine (fluoride ions and hydrogen fluoride) and heavy metal ions to generate pretreated water. A calcium compound is added to the pretreated water to generate a first insolubilized product at a pH of less than 5, followed by solid-liquid separation. A calcium compound is added to a first separated water after the solid-liquid separation to generate a second insolubilized product at a pH of 3 to 7 (provided that the pH is a pH higher than in the first reaction step), followed by solid-liquid separation. An alkali is added to a second separated water after the solid-liquid separation to give a pH of 8 or more, thereby generating a third insolubilized product, followed by solid-liquid separation.

Abstract: Described herein are methods and compounds for extracting water from an aqueous solution. For example, some embodiments include method for extracting water from an aqueous solution, comprising contacting the aqueous solution with a compound comprising one or more carbonyl moieties having an equilibrium constant for a hydration of the carbonyl moiety of at least about 0.5; separating a composition comprising the hydrated compound from the aqueous solution; and reacting the hydrated compound to obtain water.

Abstract: Sludge dewatering process assisted by flocculating reactant, said process comprising an injection of flocculating reactant into the sludge and a step of dewatering said sludge, characterized in that it comprises a preliminary step that consists in mixing said sludge in a mixer (4) comprising a cylindrical chamber (4a) equipped with blades (4c) rotatably mounted on a shaft (4b) rotating at a speed of rotation of between 500 rpm and 4000 rpm, so as to destructure the sludge and reduce the viscosity thereof, and in discharging the sludge from said mixer (4) via a network (11) to said dewatering step, and in that it comprises a step of depressurizing said mixer (4) and said network giving rise to the lysis, by cavitation, of said sludge, said depressurizing step being carried out over a period of at least 0.1 second. Corresponding plant.

Abstract: Systems and methods of restoring a lake including dredging, island creation, water treatment, real estate development, computer modeling of environmental conditions, wave height reduction, sediment removal and encapsulation, bathymetry contouring, littoral zone restoration, plant restoration, and/or fish restoration.

Abstract: A mixing apparatus for mixing substances includes a single-use apparatus and a reusable apparatus. The single-use apparatus includes a flexible mixing tank configured to receive the at least two substances to be mixed, is plastic, and has a rotor arranged in the mixing tank. The rotor includes an impeller configured to mix the at least two substances, the impeller being magnetically contactlessly drivable and free of coils and permanent magnets. The reusable apparatus includes a support tank configured to receive the mixing tank and a stator configured to magnetically contactlessly drive the rotor about an axis of rotation in an operating state. The stator includes at least one permanent magnet configured to generate a permanent magnet flux and at least one winding configured to generate an electromagnetic flux, the permanent magnet flux and the electromagnetic flux together being capable of driving the rotor.

Abstract: The present invention is directed to a fluid mixing system. In an embodiment, the fluid mixing system includes a first vessel; a second vessel disposed within the first vessel; a mixer disposed outside of the first vessel in fluid communication with the second vessel; and a media introduction port disposed outside of the first vessel in fluid communication with the mixer.

Abstract: One system embodiment includes: an inlet sensor that measures a fluid quality of an input fluid stream; an arrangement of separation units operating to extract contaminants from the fluid stream; and a user interface (UI). Each separation unit produces a respective output fluid stream, exhibiting a performance that is impacted by a respective operating parameter, and has an outlet sensor that measures an output fluid stream quality. The UI receives fluid quality measurements from the inlet and the outlet sensors, responsively derives a performance value for each separation unit and an overall performance value for the arrangement, and displays each of the performance values. The UI may further set the operating parameter values to automate and optimize the operation of the arrangement for different drilling conditions. The fluid quality measurements may indicate contaminant concentrations, and the performance values may account for separation efficiency, energy consumption, reliability, and next service date.

Abstract: A method for removal and recovery of phosphorus includes a precipitation step for precipitating phosphorus from a liquid stream comprising at most 30 mg of phosphorus per liter and at most than 50 mg of suspended solids per liter, using a precipitation agent, to form a precipitate, to form a precipitate; a first separation step for separating the precipitate from the liquid stream; a dissolution step for dissolving the precipitate in phosphoric acid to obtain a first solution; and a second separation step for separating the phosphoric acid and the precipitation agent.

Abstract: Disclosed herein are methods of producing alumina trihydrate crystals from an alumina trihydrate recovery process stream wherein an aqueous emulsion comprising a crystal growth modifier, which is at least one of an acyclic anhydride or an alkyl or alkenyl succinic anhydride, is added to the alumina trihydrate recovery process stream, wherein the aqueous emulsion is substantially free of mineral oils. The method provides a decrease in percentage of alumina trihydrate crystals having a volume average diameter of less than about 45 micrometers compared to the percentage of alumina trihydrate crystals produced in the absence of the crystal growth modifier. The process does not require the addition of a defoamer/anti-foam agent in order to control foam generated in the process.

Abstract: In accordance with one aspect of the invention a testing procedure, a processing procedure and a resulting product are provided whereby sewage sludge is primarily or firstly pre-hydrolyzed in whole or in part by means other than alkali. The alkali is then added to the pre-hydrolyzed product. The pre-hydrolyzed product from step one has a reduced potential for further hydrolysis and is more effectively stabilized in step 2 as a liquid biosolids-containing product or BSP. As a result, in accordance with the invention less of the alkali is used up in the step 2 further alkali-based hydrolysis of the pre-hydrolyzed product. The pH of the BSP product after the step 2 alkali treatment drops less over the period of storage and the BSP product will be better preserved against microbial regrowth.

Abstract: Beneficiating particulate additives by removing contaminants or minerals that impact the quality and specific gravity of the particulate additives may be achieved via dry solids separation technologies. For example, an air classifier, an electrostatic separator, and a combination thereof may be used to produce a beneficiated particulate additive comprising less than 40% of drill solids by weight of the beneficiated particulate additive.

Abstract: A method for the forced dewatering, by pressing, of saline residues produced by drinking water production, or by the treatment of municipal or industrial wastewaters, in which method the saline residues are introduced into the cylinder (12a) of a piston press (12) comprising flexible drains (12e) formed by flexible sheaths from a material that is permeable to liquid but impermeable to solids, each drain (12e) comprising an inner passage that opens into an associated opening (12g), the press operating in batches, and characterized in that during pressing, the piston carries out reciprocal movements and applies alternating and variable pressures to the sludge, while the flexible drains are deformed, the liquid pressed out from the product passing through the wall of the drains and being discharged as a filtrate, while the dewatered sludge remains outside the drains and is discharged by opening the press.

Abstract: A fluid mixing system that can be used as a bioreactor or fermentor can include a stand and a support housing pivotably mounted to the stand. The support housing bounds a chamber into which a container assembly is removably disposed. The container assembly includes a flexible bag bounding a compartment adapted to hold a fluid and a mixing element disposed within the compartment. The support housing can be tilted relative to the stand for ease in insertion of the container assembly. The support housing can also be repeatedly rocked relative to the stand form mixing fluid within the container assembly.

Abstract: Provided is a sludge drying composite conditioner. The sludge drying composite conditioner comprises a Fenton's reagent or/and Fenton-like reagent and a matrix construct, the weight ratio between the Fenton's reagent or/and the Fenton-like reagent and the matrix construct is 1:0.05 to 300, and the matrix construct is powder. Further provided is an application method of the sludge drying composite conditioner, which comprises the steps of: adding a Fenton's reagent or/and Fenton-like reagent in a sludge, performing stirring and mixing, and performing an oxidation reaction; and adding a matrix construct to the sludge added with the Fenton's reagent or/and Fenton-like reagent and performing stirring and mixing.

Abstract: Polymer flocculants are described comprising blends of high molecular weight polyethylene oxide and high molecular polyacrylamides. When introduced in desired amounts and with desired molecular weight ranges, excellent flocculation function is found that can be used to reduce polymer consumption to obtain a desired purity of clarified waste water. It has been found that the desirable polymer blends can be effectively added upstream from locations in which polyethylene oxide would generally be added so that the polymer blend can effectively mix with the slime flow to reduce or eliminate the need for excess polymer use to compensate for less effective mixing with the slime flow. Suitable waste treatment systems are described to provide for the delivery of the flocculants in the waste treatment process.

Abstract: A water testing system having a water sample container that is adapted to retain a water sample, a color indicator container that is adapted to dispense a color indicator which is adapted change the color of the water sample when the water sample contains DTC, and a colorimeter that is adapted to automatically determine a blank value and the concentration of sodium dimethyldithiocarbamate in the water sample. A method for determining the concentration of DTC in a water sample comprising providing a water testing system, placing the water sample in the water sample container, placing the water sample container in the colorimeter, automatically determining a blank value, adding the color indicator to the water sample, placing the water sample container in the colorimeter, and automatically determining the concentration of DTC in the water sample.

Abstract: Method and system for removal of heavy metal ions from a rich hydrate inhibitor stream, wherein the method comprises a) adding a selective heavy metal reactant to the rich hydrate inhibitor stream, forming a fluid stream comprising heavy metal salt particles, b) separating the obtained fluid stream in three streams a hydrocarbon stream, a recovered rich hydrate inhibitor stream, and a slurry comprising the heavy metal salt particles, c) separating remaining hydrate inhibitor from the slurry thereby obtaining a concentrated rest comprising the heavy metal salt particles.

Abstract: The present invention is to a process for reducing and removing organic phosphorus acid from waste stream. The process involves adding a multivalent metal salt to the waste stream and adjusting the pH level of the waste stream to an optimum level to maximize the removal of organic phosphorus acid.

Abstract: Polymer flocculants are described comprising blends of high molecular weight polyethylene oxide and high molecular polyacrylamides. When introduced in desired amounts and with desired molecular weight ranges, excellent flocculation function is found that can be used to reduce polymer consumption to obtain a desired purity of clarified waste water. It has been found that the desirable polymer blends can be effectively added upstream from locations in which polyethylene oxide would generally be added so that the polymer blend can effectively mix with the slime flow to reduce or eliminate the need for excess polymer use to compensate for less effective mixing with the slime flow. Suitable waste treatment systems are described to provide for the delivery of the flocculants in the waste treatment process.

Abstract: When liquefying sludge, e.g as in U.S. Pat. No. 6,808,636, the combination of temperature, pH, and shearing, is synergistic. Described here is a system that provides for collating test sampling and full-scale data inputs, recording achieved results and the engineering parameters that achieved those particular results. The data is presented in e.g a table format, which assists design engineers to zero-in on the combinations of parameters that will likely give the desired results.

Abstract: A method for extracting precious metals from a polymetallic ore, comprising a) generating hypochlorites from a salt brine; b) chlorination of the ore using hypochlorites under acidic conditions; c) filtering to collect a pregnant solution and treating the pregnant solution for collection of precious metals; d) filtering to separate the precious metals and a barren brine; e) purifying the barren brine; and f) recycling halogens from the purified brine in the form of hypohalites formed by electrolysis of the purified brine, and comprising hypochlorite and hypobromite; step b) further comprising scrubbing excess halogens using calcium hydroxide; treating the pregnant solution in step c) comprises reducing an oxydo reduction potential of the pregnant solution and using calcium hydroxide for neutralization; and step e) comprising increasing the pH of the barren brine by addition of calcium hydroxide.

Abstract: The present invention relates to methods for the separation of materials from heterogeneous fluids and provides a means of effecting stimulant-sensitive flocculation and consolidation of solid suspensions within a liquid medium. Specifically, the present invention provides a method of controlling the state of a suspension of solid particles in a liquid, including applying to the suspension a stimulus adapted to control inter-particle forces between the solid particles. The stimulus is reversibly operable to control attraction and/or repulsion. Means of consolidating a sediment bed and of separating the resultant liquids-rich and solids-rich phases are also within the ambit of the invention.

Abstract: A method of treating a wastewater is provided and can be used, for example, to treat a gas well production wastewater to form a wastewater brine. The method can involve crystallizing sodium chloride by evaporation of the wastewater brine with concurrent production of a liquor comprising calcium chloride solution. Bromine and lithium can also be recovered from the liquor in accordance with the teachings of the present invention. Various metal sulfates, such as barium sulfate and strontium sulfate, can be removed from the wastewater in the production of the wastewater brine. Sources of wastewater can include gas well production wastewater and hydrofracture flowback wastewater.

Abstract: In a process for separating a solid material from a suspension of the solid material in water, an organopolysiloxane polyalkylene oxide copolymer comprising a branched organopolysiloxane structure is added to the suspension of solid material in water and the suspension is drained. The organopolysiloxane polyalkylene oxide copolymer comprising a branched organopolysiloxane structure increases the rate of drainage of the suspension.

Abstract: The present invention relates to the recovery of nylon from co-mingled materials (e.g., carpet) with reduced or eliminated ash (e.g., calcium carbonate) contamination.

Abstract: Disclosed herein are systems and methods for removing fine particulate matter from a fluid, comprising a separator that separates an inflow fluid stream into an overflow fluid path and an underflow fluid path, where the underflow fluid path is treated with a tethering material that attaches to the coarse particulate matter to form tether-bearing anchor particles and where the overflow fluid path is treated with an activating material so that the activating material interacts with the fine particulate matter to form activated particles. After these treatments, the underflow fluid path containing the tether-bearing anchor particles is commingled with the overflow fluid path containing the activated particles, so that a removable complex is produced that can be removed in a settling facility, thereby removing the fine particulate matter from the fluid.

Abstract: Methods of producing collection tubes are presented. The methods include providing a separator substance that can rapidly polymerize in a short time to a desired hardness and disposing the separator substance within the lumen of the tube. The separator substance is formulated to have a density between an average density of a serum fraction of whole blood and a cell-containing fraction of whole blood, and to be flowable with whole blood. Upon centrifugation of a tube having blood, the separator substance forms a barrier between the whole blood fractions. The tube and barrier maintain stability of one or more analyte levels, including potassium and glucose, within 10% of their initial values before centrifugation for at least four days.

Abstract: An oil recovery process that utilizes one or more filtration medium comprises a filter cake and a second filtration medium being nonwovens sheet to remove silica and/or oil and/or dissolved organics and/or dissolved solids from produced water which includes separating oil from the produced water and precipitating silica into particles and wherein the produced water having the precipitated silica is directed to a filtration medium which operates in a direct flow filtration mode and removes the precipitated silica from the produced water to form a filtrate stream.

Abstract: Disclosed herein is a controlled method of minimizing radioactive sludge generation in treatment of wastewater from an oil and/or gas well. The method comprises measuring a concentration of a radioactive material in wastewater to be treated and measuring a concentration of barium in the wastewater to be treated. The method further comprises adding a calculated quantity of sulfate to the wastewater to be treated sufficient to precipitate a quantity of barium sufficient to reduce the concentration of the radioactive material to a level such that sludge precipitated in a secondary precipitation has a radiation level below a defined radiation level.

Abstract: Disclosed are zero liquid discharge (ZLD) processes that utilize naturally occurring or supplemental silicate in the water supply for removing magnesium and calcium hardness from aqueous alkaline streams in the form of a silica gel, thereby allowing separation of a low hardness supernant for recycling.

Abstract: A method of treating a wastewater is provided and can be used, for example, to treat a gas well production wastewater to form a wastewater brine. The method can involve crystallizing sodium chloride by evaporation of the wastewater brine with concurrent production of a liquor comprising calcium chloride solution. Bromine and lithium can also be recovered from the liquor in accordance with the teachings of the present invention. Various metal sulfates, such as barium sulfate, can be removed from the wastewater in the production of the wastewater brine. Sources of wastewater can include gas well production wastewater and hydrofracture flowback wastewater.

Abstract: A method for monitoring and controlling the chemistry of a Zero Liquid Discharge (ZLD) process in power plants is described. The method identifies the principal phenomena of precipitation of calcium sulphate and calcium carbonate which can occur in such system and the principal critical sections affected by such precipitation phenomena. The interventions aimed at keeping or restoring the sustainable chemical conditions with respect to the precipitation of calcium sulphate and calcium carbonate in all the critical sections of the ZLD system are then indicated, ensuring saturation ratios of calcium sulphate and calcium carbonate lower than or equal to 1 through time.

Abstract: Systems and methods for improving the quality of solids and liquids recovered at atmospheric pressure and temperature from a stillage stream generated as a by-product of an ethanol production process, the recovered solids having higher bio-available amino and fatty acids than evaporation-produced condensed solubles, the recovered liquids having less total solids and total suspended solids than evaporation-produced condensate. A static mixer includes an input for receiving the stillage stream combined with a GRAS anionic polymer, a cylindrical mixing chamber that controllably mixes the stillage stream and the polymer to generate wet flocculated solids and liquid co-product, and a discharge chute that outputs the wet flocculated solids and liquid co-products onto a moving, gravity filter belt having a membrane surface that separates the output from the static mixer into recovered liquids in the form of clarified, thin stillage and recovered solids in the form of dry flocculated solids.

Abstract: The invention relates to a method for solidifying a floating fat and oil in a food waste water, the method being capable of solidifying floating oil by uniformly mixing and aging the floating oil having a high content of water generated during the process of treating high concentration waste water generated during a food waste treatment process or generated from a food company, slaughterhouse and the like

Abstract: A method and system for treating waste water from hydraulic fracturing is disclosed. The treatment includes removing the sand, suspending the inorganic metals and impurities, using flocculation to engulf the impurities, and separating the impurities from the water, resulting in pure water that can be reused in the process.

Abstract: A method of conditioning, separating, drying, and comminuting sulfurous acid treated wastewater suspended solids for addition to aerobic and anaerobic digesters to provide electron donor carbon and sulfur compounds to increase the removal rate of ammonia, nitrates/nitrites, and BOD compounds.

Abstract: A system for dewatering a stream of slurry has a first and a second separator. The first separator removes objects above a first size, to produce a stream of primary treated slurry. The second separator removes objects above a second size from the primary treated stream, the second size being smaller than the first size. Optionally, a third separator removes objects above a yet smaller third size from the stream of secondary treated slurry. The first separator has a plurality of sieve mat supports alternately connected to a main support frame section and a movable support frame section so that the flexible sieve mat can be agitated by the movable support frame section, a collector being provided for collecting the primary treated slurry passing through the flexible sieve mat. In an optional step, water contained in the separated solids is removed.

Abstract: Embodiments of the invention are directed toward a novel pressurized vapor cycle for distilling liquids. In an embodiment of the invention, a liquid purification system is revealed, including the elements of an input for receiving untreated liquid, a vaporizer coupled to the input for transforming the liquid to vapor, a head chamber for collecting the vapor, a vapor pump with an internal drive shaft and an eccentric rotor with a rotatable housing for compressing vapor, a condenser in communication with the vapor pump for transforming the compressed vapor into a distilled product, and an electric motor with motor rotor and magnets hermetically sealed within the fluid pressure boundary of the distillation system.

Abstract: A method for treating phosphate-containing wastewater, such as phosphogypsum pond water. The method includes the steps of: (a) adding a first cation to the wastewater to precipitate fluorosilicate from the wastewater; (b) adding a second cation to the wastewater to precipitate fluoride from the wastewater; (c) raising the pH of the wastewater to precipitate the second cation from the wastewater; (d) removing residual silica from the wastewater; and (e) precipitating phosphate from the wastewater. The precipitated fluorosilicate may be sodium fluorosilicate. The precipitated phosphate may be struvite.

Abstract: A process removes boron from ion exchange system regeneration solution including introducing a borate precipitator into the regeneration solution in a precipitation zone to generate borate precipitate; introducing a coagulator into the regeneration solution that coagulates solids and/or borate precipitate generated by the borate precipitator and absorbs boron into the solids; introducing the regeneration solution, solids and borate precipitate into a separation zone; introducing anionic polymer into the regeneration solution adjacent to or in the separation zone to increase the propensity of borate precipitate and solids to separate from the regeneration solution; and filtering the regeneration solution to remove residual suspended solids from the regeneration solution.

Abstract: A process for treatment of water containing an azole-type anticorrosive for copper, includes adding ferrous ions to the water containing the azole-type anticorrosive for copper and having a pH of 4-8, thereby precipitating an insoluble iron-azole complex, and separating the insoluble iron-azole complex. An amount of the ferrous ions added is 0.5 to 5.0 times, by molar ratio, an amount of the azole-type anticorrosive for copper in the water containing the azole-type anticorrosive for copper. After the insoluble iron-azole complex is separated, remaining total organic carbon (TOC) components are subjected to an ozone treatment.

Abstract: The invention relates to a method for removing arsenic as scorodite from solutions that contain iron and arsenic. In accordance with the method, arsenic is first precipitated as ferric arsenate and subsequently processed hydrothermally into crystalline scorodite.

Abstract: Wastewater treatment methods and systems for removal of phosphorus (P) and nitrogen (N) from wastewater and for recovery of them as usable materials. Sufficient amount of dolomite lime and slaked dolomite lime is added into the wastewater to increase the pH of the wastewater to above 8.5 and to form P precipitates and to convert ammonium to ammonia in a precipitation-ammonia stripping reactor or a continuous flow precipitation reactor. The P precipitates are separated from the wastewater and recovered as usable solid material. The ammonia gas is absorbed and concentrated with acid solution in an ammonia absorption tower as usable liquid material.

Abstract: The invention relates to a method for recycling of phosphoric acid solution from a decontamination bath, which solution is contaminated with radioactive components, wherein the used phosphoric acid solution is diluted with aqueous oxalic acid solution, in order to separate off iron oxalate in this connection, and the phosphoric acid solution is used for decontamination of further system parts, wherein the iron ion content in the phosphoric acid in the decontamination bath is continuously measured, and phosphoric acid is continuously withdrawn from the decontamination bath and concentrated and purified phosphoric acid is replaced, so that a specific concentration of dissolved iron in the contamination bath is not exceeded, and to a system for implementation of the method.

Abstract: Embodiments of the invention provide systems and methods for water purification and desalination. The systems have a preheater, a degasser, multiple evaporation chambers with demisters, heat pipes, and a control system, wherein the control system permits continuous operation of the purification and desalination system without requiring user intervention or cleaning. The systems are capable of recovering hear from each distillation stage, while removing, from a contaminated water sample, a plurality of contaminants including: microbiological contaminants, radiological contaminants, metals, salts, and organics.